Heat exchanger



July 21, 1942. E. A.-BERTRAM HEAT EXCHANGER Filed May 1, 1940 TTORNEYPatented July 21, 1942- HEAT EXCHANGER Edward A. Bertram, Mount Vernon,N. Y., assignor to The Lummus Company, New York, N. Y., a corporation ofDelaware Application May 1', 1940, Serial No. 332,656

5 Claims, (01. 220-55) This invention relates to improvements inclosures in pressure vessels and more particularly to heads or closuresfor vessels which may be subjected alternately to pressure or vacuumconditions. a

It has heretofore been pointed out that with heavy duty pressure vesselsin which temperatures and pressures are relatively high, the effectivesealing of a closure is accomplished only with difiiculty. I haveprovided a closure for such a pressure vessel, more particularly a shelland tube type heat exchanger, which has the desirable characteristics oflow cost, simplicity, direct transfer of hydrostatic'loads from closureto vessel wall, and an externally rugged construction in which anexternal gasket is used to seal imperforate parts and by whichinspection of the pressure seal during service is accomplished.

In accordance with my invention, I provide a cover locking means forsuch a construction, which can be assembled independently of the coverand which will lock the cover against movement in either direction sothat it will be permanently fixed, even though the pressures to whichthe cover may be subjected change from superatmospheric tosubatmospheric, or vice versa.

A. more particular feature of my invention is to provide an integratedseries of rotatable dogs or shear keys for locking a closure to a vesselin which the locking dogs are supported by a common supporting ringwhich will permit their rotation, and in which a key ring is providedwhich will look all of the dogs in a predetermined-position so that theentire assembly may be freely inserted or removed and when lockedclosed, the entire series of keys is covered by the sealing gasket andleakage, except at the gasket, is impossible.

Further objects of my invention will appear from the followingdisclosure of a preferred form of embodiment thereof taken in connectionwith the attached drawing, in which pressure, which requires anexceptionally rugged channel cover l8.

tube side of such an exchanger, the tube sheet in a fixed position.

Fig. 1 is a side elevation with parts broken away and in section of ashell and tube type heat exchanger to which my invention is applied;

Fig. 2 is an end elevation with parts broken away and in section of thechannel end or floating tube sheet end of the heat exchanger shown inFig. l; 2

Fig. 3 isan enlarged vertical section showing the details of the gasketand locking dog construction;

Fig. 4 is an end elevation of a part of-a modifled form of coverconstruction showing the details of the locking dog arrangement;

Fig. 5 is a vertical section similar to Fig. 3 showing other details ofthe modified form of construction of Fig. 4. y

In accordance with the preferred form of em bodiment of my invention,the heat exchanger 10 is used to represent a type of pressure vesselwhich is subjected to elevated pressures which require an especiallyrugged closure member. Such heat exchanger has the customary tube bundleII, the one fluid for which may enter and exitthrough a channel chamberI 4 having the inlet and outlet nozzles i5 and ii. In such case thechannel chamber may be undera very high With high pressure on the cover20, which cooperates with the floating tube sheet 22, must also be of avery rugged construction. A heat exchanger of this particular type isfrequently used as a condenser with high pressure fluids on the tubeside, such pressures being in the. range of 350 lbs. per square inch andupward.

It is, of course, to be understood that the shell side of the heatexchanger is provided with fluid flow through the inlet and outletnozzles 23 and 26 and that the fluid on the outside of the tube bundlesurroundsthe tubes and the floating tube sheet cover. Under somecircumstances, the pressure on the exterior of the'tubes may exceed thepressure within the tubes, but ordinarily the pressure within the'tubesis the higher. It is, therefore, necessary that the cover 20 be heldimmovable and, for standardization and uniformity, it is desirable thatthe cover l8 be held It will be noted that in each case the cover i8vessel wall may not be the smallest diameter of the vessel. Theshoulder'26 thus formed prevents the inward movement of the cover. Otherand equally satisfactory forms of abutment-s can also be provided as,for example, a recessed ring,

but for simplicity of manufacture, the recessed 7 diameter is theeasiest to manufacture and satisfactorily serves to prevent the movementof the cover inone direction. As shown in Fig. 3, which may be a sectionof any vessel, the wall of the vessel is indicated at lfla and may beconsidered to be the wall to which a cover, generally indicated as H,may be attached.

The principal feature of my invention is th use of locking dogs or shearkeys, generally indi'-' f wall."

cated at 28,-'-to lock the cover to the-vessel within the vesselsubstantially cylindrical shank 28a and an anof my invention to usediscontinuous recesses if for any reason such construction is-foundnecessary for the purpose of greater strength.

The dogs 28 have a nominal width, that of the shank 28a, and this is thedetermining factor in the width of the recess Ila in the cover H,

which is formed by reducing the diameter of the outer .part of the coverwhich provides a continuous recess as illustrated in Fig. 2. With such arecess, it is desirable that the dogs 28 -be uniformly spaced around theperiphery of the cover, and this is effectively accomplished by aspacing or assembly ring 32 which embraces the reduced cylindricalportion 280 of the shank of the dogs 28. A cotter key 33 can -be used toestablish the fixed position of all of the dogs 28 in the spacing ring32.

corrected by variation of the tension on the studs l3 and 44.

A slightly modified form of construction is shown in Figs. 4 and 5 inwhich the vessel wall Illa is similar to the one heretofore described,

and is adapted to receive the cover II which is also of a similar sizeand shape. In this case, however, the locking dogs or shear keys 50 areslightly different in that the shankportion 50a is of substantiallyuniform diameter up to the key portion 50b and in this case, the bearingfor the shank portion 50a. is supplied by the independent recesses 30 asshown in, Fig. 4. In such case, each of the lugs is independent duringthe locking or unlocking operation and each lug must be independentlyremoved, although while locked orunlocked, they may be held in thedesired position by the locking ring 31, heretofore described. Suchconstruction may be preferred where the diameter of the holding ring 32would The shank of the dogs 28, in addition to the cylindricalbearingportion 28a and the reduced portion 280, is also preferably providedwith a key portion 28d at the end, which is of any desired polygonalconfiguration. With such a shape, the dogs 28 can be readily turned intothe holding position in'the recess lob or into the free position in therecess Ila in the cover. An indicating arrow 35, as shown in Fig. 4,will indicate' the position of the locking portion 28b.

Preferably, the .dogs 28 are all looked in a predetermined position. Ifthe cover is being disassembled, all of the dogs are turned about thelongitudinal axes oftheir shanks to their released position, in whichposition a locking ring 3'I can be placed over the polygonal shanks 28dso that all of the locking dogs can be handled as a unitand so that theportions 28b will not accidentally engage in the vessel wall. This ringis also of advantage after assembly, as when the locking dogs are allturned into locked position, the ring 31 may be replaced to lock eachdog and assure the permanence of their engagement with the vessel wall.

-The locking dogs will effectively hold the cover against outwardmovement and the shoulder 26,

heretofore mentioned, will prevent the movement of the cover in aninward direction. Regardless of changes of pressure, therefore, thecover" is in a fixed position.

Sealing of the peripheral space between the cover and the shell isaccomplished by an external gasket which permits effective inspectionand prevents hidden leaks. It more specifically embraces a pair ofannular ribs, one of which is indicated at 38 and extends from the endof the wall Na while a similar rib 39 projects from the cover H, suchribs serving as the pressure-contacting surfaces for the gasketgenerally. indicated at ll. The gasket is preferably held in position bya ring 42 which is in turn anchored tothecoverandtothevesselwallbyaseriesof studs 0 and M. The ring 42 maybe in one or two annular piecesand is adapted to exert an effective sealing pressure between the gasketand the respective cover and vessel wall ribs. As the gasket is on theoutside of the cover andthe vessel wall and completely covers alllocking lugs, etc, any leaks can be readily ascertained and -myinventionvwithin the scope and spirit 'of the where the size of the dogis predetermined and be so great as to be impractical. Uniformperipheral spacing is obtained in a satisfactory manner by this means.

It is, of course, to be understood that the shear keys have theprincipal function of serving as a mechanical lock between the cover andvessel wall and the keys might be recessed in the vessel wall, if itwere sufficiently thick, and be turnedinto position by a stem onshankprojecting out of the vessel wall. Preferably, the vessel wall should beimperforate to avoid any possibility of leaks, and the reduced coverdiameter appears to .be cheapest for the desired purpose. The keys couldbe readily placed, part in the cover and part in the vessel wall, if anyadvantage would result from such an arrangement. As the cover need notbe turned to release the holding eymeans, the shape may be polygonal orother than circular, if such shape is found more advantageous inparticular cases.-

While I have shown and described a preferred form of embodiment of myinvention, I am aware that modifications may be made thereto and Idesire, thereforefa broad interpretation of description herein and ofthe claims appended hereinafter.

I claim: r

1. A pressure vessel of the class described having an opening, a coverfor said opening, said cover being-smaller than the opening and adaptedto fit therein, the vessel wall adjacent said opening having a shoulderto limit the movement of the cover into the opening, means to resist thetendency of the cover to move out of the vessel under internal pressure,and means to seal the joint between the cover and the vessel, said coverbeing provided with an external peripheral recess extending partiallyacross the thickness of the cover,-the wall of said vessel adjacent tothe opening having an internal circumferential recess in line with thebase of the cover recess, the covermovement resisting means consistingof a series of rotatable keys each having a shank portion extendinglongitudinally along the margin of the cover and being rotatable aboutthe longitudinal axis of its shank portion, said keys having an angularportion of" substantially the same width as the recess in the wall ofthe vessel and rotatable into and out of said wall recess, whereby whensaid keys are in appropriate p0- sltion, the angular portions will be inclose fitting shear relation to resist outward movement of the cover.

ring positioned in the peripheral recess of said 2. A pressure vessel asclaimed in claim 1 in which the externallperipheral recess in the coveris continuous and an assembly ring-fits within said recess and engagesand spaces each of the key means whereby the key means may be handled asa unit.

3. A pressure vessel of the class described in claim 1 in which theshank portion of each of the key means has a polygonal portion, and alocking ring having polygonal openings engages said shank portions tolock the key means against turning from either the locked or unlockedposition.

4. A pressure vessel of the class described in claim 1 in which anassembly ring engages and spaces each of the key means whereby the keymeans may be handled as a unit, and a locking cover, each of the shankportions being keyed to the locking ring to lock the key means againstturning from either the cover locking or unlocking position-and therecess in the cover is of sufficient depth and width to receive theentire key means, assembly ring, and locking ring.

5. A pressure vessel as claimed in claim 1 in which the externalperipheral recess is provided with spaced radial outwardly openingnotches to space the key means and form a bearing therefor, and alocking ring positioned in the peripheral recess of said cover, each ofthe shank portions being keyed to the locking ring to lock the key meansagainst turning from either the cover looking or the unlocking position.

' EDWARD A. BERTRAM.

